Back to EveryPatent.com
United States Patent | 6,009,220 |
Chan ,   et al. | December 28, 1999 |
A surveillance system for in-service fault identification in an amplified passive branched optical network is provided. This system does not require any wavelength tunable light source as used in multi-wavelength OTDR. Fiber-Bragg gratings are placed at some strategic positions on different fiber branches to slice and reflect the optical amplifier's residual ASE power at some wavelength other than the signal wavelengths. The conditions of the fiber link and optical amplifier at each branch can be monitored by constantly checking the reflected power level of the corresponding wavelength without suspending the in-service channels.
Inventors: | Chan; Chun-Kit (Rm 1207, Wah Sang House, Wah Fu Estate, HK); Chen; Lian-Kuan (23B, Block 13, City One, Shatin, N.T., HK); Tong; Frank F. K. (UR14 Flat 5A, The Chinese University of Hong Kong, Shatin, HK); Lam; Dennis K. W. (Patios 5 Bangai, 418 12 Utase, 2 Chome, Mihama-ku, Chiba, JP) |
Appl. No.: | 989921 |
Filed: | December 12, 1997 |
Jan 15, 1997[CA] | 2195153 |
Current U.S. Class: | 385/24; 385/37; 398/20 |
Intern'l Class: | G02B 006/28; H04B 010/08 |
Field of Search: | 385/24,37,12 359/110 |
5329392 | Jul., 1994 | Cohen | 359/124. |
5446809 | Aug., 1995 | Fritz et al. | 385/17. |
5530666 | Jun., 1996 | Kashyap et al. | 365/123. |
5570440 | Oct., 1996 | Mizrahi | 385/37. |
5771250 | Jun., 1998 | Shigehara et al. | 372/6. |
5774606 | Jun., 1998 | De Barros et al. | 385/24. |
5907417 | May., 1999 | Darcie et al. | 359/110. |
OFC 1996 Technical Digest, Optical Fiber Identification System Using Fiber Bragg Gratings, Shigehara et al, 1996. A Passive Surveillance Scheme for Passive Branched Optical Networks C.K. Chan; F. Tong; L.K. Cheng; J. Song; D. Lam OFC'97 Dallax, TX, Paper TuK1 (1997). A Practical Passive Surveillance Scheme for Optically-Amplified Passive Branched Optical Networks C.K. Chan; F. Tong; L.K. Chen; J.Song; Dn. Lam IEEE Photonics Technology Letters, 1997. Fault Location Technique for In-Service Branched Optical Fiber Networks I. Sankawa; S.I. Furukawa; Y. Koyamada; H. Izumita IEEE Photonics Technology Letters vol. 2 No. 10, Oct. 1990. Measuring the Individual Attenuation Distribution of Passive Branched Optical Networks K. Tanaka, M. Tateda, Y. Inoue IEEE Photonics Technology Letters vol. 8, No. 7, Jul. 1996. Recent progress in OTDR technologies for maintaining optical fiber networks Y. Koyamada, T. Horiguchi, S. Furukawa IOOC 1995. Fault-Locating and Supervisory Technique for Multistaged Branced Optical Networks Y.K. Chen, S. Chi IEEE Photonics Technology Letters, vol. 6, No. 7, Jul. 1991. In-service Remote Access and Measureent Systemf or Passive Double Star Networks F. Yamamoto, I. Sankawa, S. Furukawa, Y. Koyamada Journal of Optical Communications (1995). Optical Fiber Identification Using Rayleigh Backscattred Light T. Kuwabara, H. Koga, Y. Kato, Y. Mistunaga IEEE Photonics Technology Letters, vol. 4, No. 7, Jul. 1992. Characterization of a 16-Channel Optical/Electronic Selector for Fast Packet-Switched WDMA Networks F. Tong, C.S. Li, A.E. Stegvens, Y.H. Kwark IEEE Photonics Technology Letters, vol. 6, No. 8, Aug. 1994. Characterization of a variable bit-rate receiver for applications in WDM/WDMA systems F. Tong, C.S. Li, G. Berkowitz OFC ' 96 Technical Digest (1996). |